b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
142 lines
4.3 KiB
Groff
142 lines
4.3 KiB
Groff
.\" $NetBSD: tsearch.3,v 1.12 2010/04/30 10:09:23 jruoho Exp $
|
|
.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. The name of the author may not be used to endorse or promote products
|
|
.\" derived from this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
|
|
.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
|
|
.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
|
|
.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
|
.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
|
.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
|
|
.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
|
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
|
|
.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
|
.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" OpenBSD: tsearch.3,v 1.2 1998/06/21 22:13:49 millert Exp
|
|
.\"
|
|
.Dd April 30, 2010
|
|
.Dt TSEARCH 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm tsearch, tfind, tdelete, twalk
|
|
.Nd manipulate binary search trees
|
|
.Sh SYNOPSIS
|
|
.In search.h
|
|
.Ft void *
|
|
.Fn tdelete "const void * restrict key" "void ** restrict rootp" "int (*compar) (const void *, const void *)"
|
|
.Ft void *
|
|
.Fn tfind "const void *key" "const void * const *rootp" "int (*compar) (const void *, const void *)"
|
|
.Ft void *
|
|
.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)"
|
|
.Ft void
|
|
.Fn twalk "const void *root" "void (*action) (const void *, VISIT, int)"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn tdelete ,
|
|
.Fn tfind ,
|
|
.Fn tsearch ,
|
|
and
|
|
.Fn twalk
|
|
functions manage binary search trees based on algorithms T and D
|
|
from Knuth (6.2.2).
|
|
The comparison function passed in by
|
|
the user has the same style of return values as
|
|
.Xr strcmp 3 .
|
|
.Pp
|
|
.Fn tfind
|
|
searches for the datum matched by the argument
|
|
.Fa key
|
|
in the binary tree rooted at
|
|
.Fa rootp ,
|
|
returning a pointer to the datum if it is found and NULL
|
|
if it is not.
|
|
.Pp
|
|
.Fn tsearch
|
|
is identical to
|
|
.Fn tfind
|
|
except that if no match is found,
|
|
.Fa key
|
|
is inserted into the tree and a pointer to it is returned.
|
|
If
|
|
.Fa rootp
|
|
points to a NULL value a new binary search tree is created.
|
|
.Pp
|
|
.Fn tdelete
|
|
deletes a node from the specified binary search tree and returns
|
|
a pointer to the parent of the node to be deleted.
|
|
It takes the same arguments as
|
|
.Fn tfind
|
|
and
|
|
.Fn tsearch .
|
|
If the node to be deleted is the root of the binary search tree,
|
|
.Fa rootp
|
|
will be adjusted.
|
|
.Pp
|
|
.Fn twalk
|
|
walks the binary search tree rooted in
|
|
.Va root
|
|
and calls the function
|
|
.Fa action
|
|
on each node.
|
|
.Fa Action
|
|
is called with three arguments: a pointer to the current node,
|
|
a value from the enum
|
|
.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;"
|
|
specifying the traversal type, and a node level (where level
|
|
zero is the root of the tree).
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn tsearch
|
|
function returns NULL if allocation of a new node fails (usually
|
|
due to a lack of free memory).
|
|
.Pp
|
|
.Fn tfind ,
|
|
.Fn tsearch ,
|
|
and
|
|
.Fn tdelete
|
|
return NULL if
|
|
.Fa rootp
|
|
is NULL or the datum cannot be found.
|
|
.Pp
|
|
The
|
|
.Fn twalk
|
|
function returns no value.
|
|
.Sh SEE ALSO
|
|
.Xr bsearch 3 ,
|
|
.Xr hsearch 3 ,
|
|
.Xr lsearch 3
|
|
.Sh STANDARDS
|
|
These functions conform to
|
|
.St -p1003.1-2001 .
|
|
.Sh CAVEATS
|
|
The
|
|
.St -p1003.1-2001
|
|
standard does not specify what value should be returned when deleting
|
|
the root node.
|
|
Since implementations vary, user of
|
|
.Fn tdelete
|
|
should not rely on any specific behaviour.
|
|
The
|
|
.St -p1003.1-2008
|
|
revision tried to clarify the issue with the following wording:
|
|
.Do
|
|
the
|
|
.Fn tdelete
|
|
function shall return a pointer to the parent of the deleted node,
|
|
or an unspecified non-NULL pointer if the deleted node was the root node, or a
|
|
.Dv NULL
|
|
pointer if the node is not found
|
|
.Dc .
|